Quote1 And what if they are bats, Mr. Wayne? What then? Destroy them like insects? We won't survive the next evolutionary cataclysm but bats will! Quote2
-- Robert March src

Doctor March became obsessed with bats and spent most of his professional years studying them in order to find a way to give humans bat-like features. However, most of his research was never tested and all his projects were left as theoretical studies.

Years later, his son-in-law Kirk Langstrom used March's studies to continue them and to finally accomplish March's dream. In this way, the serum that originated the Man-Bat was created.

It was up to Batman to stop Man-Bat and revert his transformation.[1] When March learned that his experiments have caused his own daughter to transform into the Man-Bat creature, he finally understood the risk of his power play and destroyed his research for good.[2]